1. Field
The present disclosure relates generally to an image forming apparatus and a method for controlling the same, and more particularly, to an image forming apparatus and a method for controlling the same, which can implement a low-power mode.
2. Description of the Related Art
Recently, a demand for low power consumption of all electronic appliances has been gradually strengthened, and the electronic appliances which do not cope with such a demand, even if they have an advantage in performance and price, cannot be sold due to the corresponding regulatory restriction.
The current specification of Energy Star requires that power consumption in a standby mode is equal to or less than 1 to 2 W according to the type of appliance. Hereafter, even in a standby state where a network service is possible, power consumption of equal to or less than 1 W will be required, and all electronic companies have mobilized various methods to comply with this requirement.
Further, it is required for a consumer not to feel inconvenience depending on whether the appliance is in a low-power state or in a normal operation state.
According to a current method that most companies approach to achieve a low-power standby mode, a high-performance main CPU and an auxiliary CPU that consumes low power are configured, and in a normal mode, a service is provided through the main CPU, while if the system enters into a standby mode in compliance with a specified condition, the main CPU and unnecessary system power are turned off and monitoring of a service request is performed through the auxiliary CPU. In this case, if a user requests a service, the auxiliary CPU applies the power to the main CPU and auxiliary circuits to provide the requested service. That is, in addition to the existing CPU cores, a separate CPU having a small gate size is to be added.
As an example, a system in the related art is provided with a sub-controller that is mounted thereon in addition to the main controller to recognize IO reception and wakeup processing events in a low-power mode and to apply the power to the main controller. In this case, since a separate chip is mounted, the price is increased, and separate circuits and software for communication between the main controller and the sub-controller are required.
As another example, CPUs of the main controller and the sub-controller are integrated into one SoC, and in a service mode, the main controller controls MAC, USB, Fax, and IO ports, while in a low-power mode, the sub-controller processes data such as MAC, USB, Fax, and IO ports. Even in this case, it is necessary to add a separate CPU for low power.